Description:

Pop the top byte off of the stack and add it to the new top byte on the stack.

Pseudo Code:

byteVal = stack[sp - 1]
sp = sp - 1
stack[sp - 1] = stack[sp - 1] + byteVal
pc = pc + 1

Flags Affected:

D	H	C	Z	N

Possible Errors:

tvmStackUnderflow

-

There were not enough bytes in the stack.

Example:

addb

Before stack   top 1 0x0B 2 0x17   bottom

After stack   top 1 0x22   bottom